When developing his Playgroup project in the late 1990s, Trevor Jackson made hundreds of tracks. Since only a few of these were turned into finished tracks for the eventual 2001 set, he was left with a vast archive of unreleased material. It's this that he's mined for Previously Unreleased, a superb two-disc set of typically far-sighted material. While there are plenty of tracks that explore a similar range of influences to the original album - think punk-funk, dub and electrofunk, for starters - Previously Unreleased also includes a string of killer, acid-house inspired dancefloor workouts, an Italo-disco shuffler ("Doin' It Right"), a freestyle jam ("Live at the Funhouse") and a sprawling, post-rock ambient soundscape ("Little Things", featuring a young Kieran 'Four Tet' Hebden on guitar).